By Phil Parry, BBC Wales
Presenter of Panorama investigation into South Wales Police
The devastating consequences of any miscarriage of justice case are clear for anyone to see, and not simply for those who spent years in jail for crimes they did not commit.
Annette Hewins had a breakdown when she was in prison
The victim's family, too, are tortured by the knowledge that the real killer has remained free, often for years.
Annette Hewins was wrongly jailed following an arson attack on the Gurnos estate in Merthyr Tydfil. She was released on appeal after spending two-and-a half-years in prison.
She, like other victims of miscarriages, lives the trauma of what happened to her every day.
In prison, her new-born baby was taken away from her, she suffered a nervous breakdown and turned to drugs becoming a heroin addict.
"I don't think anyone who has suffered a miscarriage of justice can really sum it all up, it's unreal, it's like as if it's happened to somebody else," she told me.
"When I was in prison in the cell, I would look around and I'd think, I'm in prison, I'm really in prison, and I'd think, well, I haven't done nothing wrong, and I'd think well, I shouldn't be in here, I want to go home now."
With the miscarriages cases in south Wales, one thing becomes clear when you talk to those innocent people who have been jailed.
They are all utterly consumed by the injustice of what has happened to them and they all, to a lesser or greater extent, have problems adjusting to normal life once they are released.
Their lives, very often, revolve around righting the wrong. They can talk lucidly and in enormous detail of the facts of the case, including the dates, even times, that events took place.
But when it comes to organising their lives or relating to their own family and friends, it becomes far, far harder.
Mike O'Brien holds the unenviable record as Wales' longest miscarriage of justice victim. He served 11 years in jail for a murder he did not commit, the killing of a newsagent in Cardiff, before his release in 1998.
He has doggedly pursued the police for what happened to him, launching a legal action which is grinding its way through the courts.
For him, like the others, any compensation money is not an issue. It is having their names fully cleared, and the police officers who were part of the investigation team held to account for what they did.
Arson at this house led to Annette Hewins' wrongful imprisonment
"I want those officers on the stand, I want them to feel like I felt when I was in the dock. The difference is they are guilty and I was innocent," he said.
Mike O'Brien would be the first to admit he has had huge problems adjusting to normal life.
He is on medication to control his mood swings, and is paranoid about much that goes on in the outside world. He has his own video security system outside his home.
But for the families of the murder victims the torment is, perhaps, even worse. They have suffered a grievous loss and a traumatic trial, only to discover years later that the killer is still free.
There is no closure. Justice has not been done.